Related Experiment Video
Updated: May 21, 2025
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
Stereo- and regioselectivity in nitrile oxide cycloaddition reactions to norethisterone acetate as dipolarophile
Giuseppe Faita1, Mariella Mella1, Paolo Quadrelli2
1Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy.
Abstract:
Benzo- and anthracenenitrile oxides undergo 1,3-dipolar cycloaddition reactions with 17 α- acetate norethisterone affording the expected isoxazoline and isoxazoles derivatives in good yields and as single regioisomers. The structures of all the new compounds were elucidated on the basis of the corresponding analytical and spectroscopic data, which were presented and discussed. The stereo- and regiochemical outcome of the cycloadditions were also accounted on the basis of 1,3-dipolar cycloaddition theory and computational investigations. Electronic (Frontier Orbital theory) and steric effects are at work in orienting selectively the cycloaddition to specific regioisomeric steroids.
More Related Videos
10:17Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
07:30A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones
Published on: January 21, 2020
Related Concept Videos
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Regioselectivity of Electrophilic Additions-Peroxide Effect
Acid-Catalyzed Ring-Opening of Epoxides
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.